The aim of this proposal is the continued study of the quantitative and qualitative changes with age in the proteoglycan-keratan sulfate (KS) fractions of human and animal cartilage, and to compare these changes with those of the keratan sulfate of aging human and bovine corneas. A search will be made to find similar fractions in nucleus pulposus. An attempt will be made to work out methods to determine and quantitate keratan sulfate fractions by immunological procedures in tissue extracts and in the proteoglycans prepared from tissues. An additional goal of this work is the search for controlling factors responsible for the aging changes in cartilage matrix.